Mycobacterium tuberculosis transmission in China during the COVID-19 pandemic period (2020–2021) compared with the pre-pandemic period (2017–2019)

The COVD-19 pandemic has led to major impacts on population-level transmission of respiratory viral illnesses. However, the impact of the pandemic on Mycobacterium tuberculosis transmission is unknown. Schoolchildren from 12 cities in Jiangsu Province were administered tuberculin skin tests at school matriculation from 2017-2021. We conducted an interrupted time-series analysis to compare trends from annual tuberculin surveys before (2017-2019) and during pandemic-related social restrictions (2020-2021). We compared observed trends in tuberculin positivity during restrictions to a counterfactual model assuming background trends prior to restrictions continued linearly. From 2017-2021, 1,940,735 schoolchildren from 1,427 schools were administered a skin test. Among middle school students, tuberculin positivity was largely consistent from 2017-2019 (9.3%, 9.6%, 10.0%), but reduced in 2020 and 2021 (8.0% and 7.0%). There was a reduction in the annual risk of infection of 24.7% (95% predictive interval [PI], -27.2, -21.2) and 37.0% (95% PI, -40.8, -33.3) compared to the counterfactual model in 2020 and 2021. Among high school students, similar but more modest reductions in the annual risk of infection were seen in post-pandemic years (19.8% reduction in 2021). There have been substantial population-level decreases in M tuberculosis transmission among adolescents in eastern China.